Ever wondered why out of all the masses of UPS choices you have there seems to be some more expensive than the others? Think of it, you can get a 1KVA UPS for under £100 and yet some people are offering 1KVA systems for over £500! Why?
Well, the answer lies in the technology – Online Uninterruptible Power Supplies. Traditionally called online double conversion, and now properly referred to a VFI (Voltage Frequency Independent) systems. So what makes them better?
Firstly, lets think about the topology, that is, the basic design elements:
The incoming power is rectified into DC and that forms a DC buss onto which the batteries sit (in practice it’s more complicated than this, but the overall effect is the same). This DC is then taken and converted to AC through the inverter. This then powers the load. So what’s so good about this?
Well, what’s happened is that the output is now independent of the input, thereby eliminating a whole raft of potential power protection problems. As a guide you will get protection from surges, brown outs, white outs, blackouts, transients, noise, frequency variations, harmonic distortion, undervoltage, overvoltage, spikes. In fact, practically all power problems can be solved with an online uninterruptible power supply.
If the power fails then the DC buss is maintained, not by the rectifier, but by the batteries sitting on the DC buss. As a result, the load sees no break. In fact it doesn’t care if the mains is there or not – it sees the same power waveform all of the time.
Is that all? Well no, there’s more. Online UPS Systems also contain a Bypass. If there’s a problem with the load (i.e. you connect too much and the UPS overloads) then the UPS will switch to bypass, protecting the UPS and allowing power to the load during this fault. When the fault clears, the unit returns to normal operation. Or if the UPS develops a fault, overheats for example, then the UPS will shut off but divert power through the bypass. In any event, power is still channelled through to the load – so the uptime is significantly improved.
Anything else? Well there is. As an Online UPS System is designed to operate on inverter all of the time (unlike other technologies which operate on inverter some of the time) they are ideal for long runtime applications. You can connect as many batteries as you can safely charge and the unit can run indefinitely.
OK, any drawbacks. Well, there are two. The first is audible noise. The UPS operates on inverter all the time and so needs a fan to keep it cool. This means that it’s not really the ideal choice for power protection in a quiet environment, although the fan noise is not much more than the typical computer system, you will notice it when compared with fanless technologies. The second is efficiency. As the AC power is rectified some power is lost, and again when it is inverted, so we lose 10-15% power during the conversion process. These power losses can add up of course, but keep in mind the losses you could sustain if you lost data due to a power disturbance.
That aside, Online Uninterruptible Power Supplies are the preferred choice of power protection for many critical applications, due to the fact that all bases are covered. Those in the know about UPS Systems will not chance any other technology and we would recommend you to do the same.
We hope we’ve shown you why Online Uninterruptible Power Supplies are the best power protection system, and not only that here at UPSMart we are bringing them to you at the best possible prices. Visit the section on Online Uninterruptible Power Supplies at the UPSMart Shop.